As is disclosed in Patent Document 1, a hook surface fastener has protruding engagement elements in a hook shape, a mushroom shape, or an arrowhead shape formed to protrude on a base. The protruding engagement elements are ordinarily formed to stand substantially vertically from the base. Accordingly, in an engaged state with an engagement counterpart (loop surface fastener, or the like), the surface fastener exhibits a certain engagement force against tensile forces both in a shear direction (direction horizontal to the surface) and the vertical direction.
Patent Document 2 and Patent Document 3 each disclose a surface fastener including protruding engagement elements tilting in one direction on a base to thereby have an engagement force that differs depending on a tensile direction. This increases the engagement force in a specific direction.